In a thin film transistor liquid crystal display (TFT-LCD), a voltage is applied between a pixel electrode (e.g., an ITO (indium-tin oxide) electrode) and a common electrode (e.g., an ITO electrode) to form an electric field; by controlling the magnitude of the voltage, and thus controlling the rotation degrees of liquid crystal molecules, a light valve is achieved.
Depending on different arrangements of positive and negative electrodes, a TFT-LCD may, in terms of structures, comprise two types: an in-plane switching (IPS) type and an advanced super dimension switching (ADSDS or ADS) type. In a liquid crystal display of an IPS-type display mode, spacing between electrodes is very small, and an in-plane electric field is generated between electrodes when a voltage is applied; liquid crystal can only make in-plane rotation in order to act as a light valve, and therefore, the light transmission is restrained. In a liquid crystal display of an ADS-type display mode, a multi-dimensional electric field is formed from an electric field generated from edges of slit-electrodes in a same plane and an electric field generated between a slit-electrode layer and a plate-like electrode layer, enabling liquid crystal molecules in all orientations between the slit-electrodes and directly above the electrodes within a liquid crystal cell to rotate, thereby improving work efficiency of the liquid crystal and increasing light transmission efficiency. The ADS technology can improve image quality of a TFT-LCD product, and has advantages of high resolution, high transmittance, low power consumption, wide viewing angle, high aperture ratio, low chromatic aberration, and free of push Mura, etc.
As shown in FIG. 1, it is a cross-sectional view of a structure of a conventional ADS-type display. The structure of the ADS-type display comprises: a color-filter substrate C and an array substrate A, as well as a liquid crystal layer 5 filled between the color-filter substrate C and the array substrate A. The color-filter substrate C comprises a glass substrate 2 and a color-filter layer 6, and the array substrate A comprises a glass substrate 71, a pixel electrode layer 3, a common electrode layer 4 and an insulating layer 72. In addition, polarizers 1 are affixed to both the respective outer sides of the color-filter substrate C and of the array substrate A. Positive and negative electrodes of the pixel electrode layer (plate-like electrode) 3 and the common electrode layer (slit-electrode) 4 are separated by the insulating layer 72 and thus arranged overlapped. During operation, the above-described electrode layers, after power is supplied, produce a multi-dimensional electric field, causing all liquid crystal molecules between the electrodes and above the electrodes to rotate within a plane of the panel.
FIG. 2 is a schematic structural view for illustrating pixel electrodes (e.g., ITO electrodes) 31 in the pixel electrode layer 3 and common electrodes (e.g., ITO electrodes) 41 of the common electrode layer 4, in the structure of the above-described conventional ADS-type display. As to a consideration of aperture ratio, capacitive coupling effect, and other factors in the design, a certain distance is present between an edge of the pixel electrode 31 and an edge of the common electrode 41, which will produce a non-uniform light-transmission phenomenon on edges of a pixel, causing a non-uniform light-transmission effect of the liquid crystal display as a whole.